return xml gz archive

function generate_sitemap()
{
    //generate sitemap
    $sitemap = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" />');
    
    //add some urls
    $url = $sitemap->addChild('url');
    $url->addChild('loc', 'http://www.url.com');
    $url->addChild('lastmod', date('Y-m-d'));
    $url->addChild('changefreq', 'daily');
    $url->addChild('priority', '1.0');
    
    //save to disk
    $fp = fopen(__DIR__.'/sitemap.xml', 'wb');
    fwrite($fp, $sitemap->asXML());
    fclose($fp);
    
    //return sitemap as a string
    return $sitemap->asXML();
}
``